[The tone of sympathetic and expression of beta1 receptor in the dogs with sustained atrial fibrillation].

Objective: To detect the influence of sustained atrial fibrillation on autonomic nerve.

Methods: 7 healthy mongrel dogs were paced at 600/min. ter sustained reversing into sinus rhythm. HRV was obtained by Holter. Noradrenaline in left atrial appendage, left atrial, atrial septal, right atrial appendage and right atrial was detected. Nerve growth factor was determined and beta1 receptor in atrial myocardium was evaluated. All the indexes were compared with control animals.

Results: ter sustained, the tone of sympathetic increased. LF in dogs with long term (1682 +/- 362) ms2 and short term (1247 +/- 219) ms2 were higher than control dogs (798 +/- 154) ms2 (P < 0.01). The HF in dogs with long term (232 +/- 75) ms2 and short term (310 +/- 165) ms2 was lower than control dogs (1041 +/- 195) ms2 (P < 0.01). The SDNN [long term (32 +/- 7) ms, short term (51 +/- 7) ms] and HRV indexes (long term 16 +/- 4, short term 24 +/- 8) in group were inferior to corresponding indexes in control group [(103 +/- 14) ms and 38 +/- 5 respectively, P < 0.01]. The content of noradrenaline in myocardium was higher in group (P < 0.01). Furthermore, the increase of noradrenaline in the atrium was heterogeneous (P < 0.01), which was not observed in control group. The expression of NGF increased in group. beta1 receptor down regulated in group.

Conclusion: Sustained caused increased tone of sympathetic, heterogeneous accumulation of noradrenaline and down regulation of beta1 receptor, which was mediated by NGF.